An increasing number of American women are seeking estrogen replacement therapy (ERT) after menopause. In addition to physical benefits, e.g.g, decreased risk of osteoporosis, heart disease,and colon cancer, several studies have suggested an efficacy of ERT in tempering age-related memory loss and reducing the risk of Alzheimer's Disease. The mechanism of these cognitive benefits remains unclear. The current study will examine the effects of ERT on behavioral and electrophysiological indices of memory function. Specifically, healthy post menopausal women drawn from a representative community sample who have undergone long- term ERT and age-matched controls, who have never used ERT, will be compared to younger premenopausal women on tests of recall, recognition, and recency memory. Beyond providing a better description of the behavioral effects of ERT, we are interested in examining potential neural mechanisms by which estrogens modulate memory function. To that end, event-related brain potentials (ERPs) will be recorded during the experimental tasks in an initial attempt to elucidate the electrophysiological indices of ERT-related memory enhancement. Overall, this work will serve as (1) a feasibility study for subject recruitment, (2) a basis for estimating effect sizes, (3) a means to better elucidate the type of memory enhancement associated with ERT, and (4) an initial examination of brain-behavior associations related to the memory effects reported in ERT-using postmenopausal women.